ANCHORS AND ANCHORING

An anchor is used by ships, boats, rigs, any other type of floating object to avoid drifting due to current or wind. They are used from ancient times when anchor could be a stone dropped on the bottom until today multitude of  anchors’ types. There are many types of anchors designed to satisfy specific needs for specific vessels. Heavy anchors, light anchors, stock anchors, stockless anchors and list can go on.

Types of anchors

1. Stock anchors are an old type of anchors with a superior holding power. Due to difficult stowing of such type of anchor they are not used anymore on merchant ships.

admiralty anchor 

2. Stockless anchors are of many types and designs, having more or less holding power depending on design and scope of use. They usually have crown, flukes and palms forged in a single piece to ensure a heavy head.

AC-14	Baldt	Byers	Danforth
D-hone	Delta	Drag	Gruson
Hall	Klipp	Moorfast	Pool
	Spek	Union

3. Lightweight anchors are made of lighter materials and designed with large flukes to have holding power in sand bottoms. They will dive deep into bottom and can be used also as stream or kedge anchors. Bruce or claw anchors are used by boats for a short stop in shallow waters because they are easy to set and won’t penetrate deep.

Bruce ss	Bruce ts	LWT

Anchoring unified requirements – IACS

Calculating the distance for ship to stop

S = v² / 2a

V² = v₀ + 2aS

F = ma = Dv²/2gS

V – speed;  v₀ – final speed(zero);  a- deceleration;  g – gravitational acceleration; D – displacement;  S – distance

Anchoring procedures

a. determine length of cable

- standard  L_C = (d_W x2 + 90) / 27.5

- bad conditions (wind, current, hard sea bottom)  L_C = (d_W x3 + 140) / 27.5

d_W  -  water depth

b. preparation of anchoring – estimate water depth, anchoring position, winch to use, method of approach

c. routine checks (winch / brakes, power unit, anchor light, communication, crew safety)

d. drop anchor following procedures according to winch type, ship type and size, other procedures as per marine and company practice

Types of moorings

	Open moor – vessel anchored with both anchors leading ahead
	Standing moor - vessel required to moor with bridge along a line
	Baltic  moor - used when construction of the berth is not strong enough to withstand in bad weather
	Mediterranean moor - used to secure vessel stern to berth

Proper procedure for anchoring and mooring

Anchoring standard safety

Anchoring large vessels